CO sensing properties of titanium and iron oxide nanosized thin films

We present a simple and reproducible method to obtain TiO2 and Fe2O3 mixed oxide thin films by reactive RF sputtering. The influence of iron concentration to the structural properties of the grown layers has been studied. Structural characterization, carried out by TEM analysis allows us to correlate the inhibition of grain growth in titania films due to the presence of iron and to its segregation at the grain boundaries. This behavior should be ascribed to superficial tension phenomena. We have investigated the gas sensing properties toward CO, with particular focus on the role of iron. The layers are capable to sense CO down to the level requested for environmental monitoring. As iron concentration in the thin film increases the response toward CO becomes higher. (C) 2001 Elsevier Science B.V. All rights reserved.